re PR c++/80593 (GCC 7, aligned_storage and “dereferencing type-punned pointer will break strict-aliasing rules”)

2017-05-19  Richard Biener  <rguenther@suse.de>

	PR c++/80593
	* c-warn.c (strict_aliasing_warning): Do not warn for accesses
	to alias-set zero memory.

	* g++.dg/warn/Wstrict-aliasing-bogus-char-2.C: New testcase.
	* g++.dg/warn/Wstrict-aliasing-6.C: Adjust expected outcome.

From-SVN: r248269